The present invention relates generally to telecommunication systems and in particular, to methods and devices for transferring data from a first telecommunication device to a second telecommunication device and/or for retrieving data.
In classical telecommunication networks, like wireless telecommunication networks, a base station transfers and/or receives data to and/or from user equipments.
In some wireless telecommunication networks, the overall system bandwidth is partitioned into plural carrier frequencies on which orthogonal signals are mapped.
The base station and the user equipments are able to transfer data through a same frequency band. Thus, the base station and the user equipments use the same modulation and/or demodulation carrier frequency and the frequency bands have the same bandwidth.
Recently, some wireless telecommunication networks allow the base station to transfer and/or receive data in a frequency band which has a larger bandwidth than the one used by some user equipments.
Such technique enables the user equipments which have different capabilities in term of bandwidth to communicate with the base station.
The problem with such technique is that the overall frequency band of the base station may not be used efficiently.
In order to use more efficiently the overall frequency band of the base station, the user equipments should be able to have different modulation and/or demodulation carrier frequencies.
The existence of different modulation and/or demodulation carrier frequencies generates some problems. If the base station maps data on the demodulation carrier frequency of a user equipment, the data may be, after demodulation by the user equipment, mixed with continuous components depending on the user equipment architecture. Strong interferences may arise from these continuous components, so that data, received in this demodulation carrier frequency are very unreliable.
Similarly, if a user equipment maps the data on the demodulation carrier frequency of the base station, the data may be, after demodulation by the base station, mixed with continuous components depending on the base station architecture. Strong interferences may arise from these continuous components, so that data, received in this demodulation carrier frequency are very unreliable.